ST. LOUIS -- Michael Wacha reached what he described as "a new milestone" in his rehab process when he took the Busch Stadium bullpen mound on Saturday afternoon and threw 30 pitches.

It had been nearly two months since Wacha had pitched off a mound, that last time being his June 17 start against the Mets. The Cardinals announced soon after that outing that Wacha had been diagnosed with a stress reaction in his right shoulder. After several weeks of rest, Wacha resumed throwing on flat ground this month and was recently cleared for this next step.

"It's one of those deals that whenever you're cleared to throw, it's a big day for you," Wacha said. "Whenever you're cleared for your first 'pen, it's a big day. But I know it's still a long road to go. I'll keep working hard and stay the course.

"It felt good to get back out there on the mound, the first time in a while. My arm felt great."

Pitching at low intensity, Wacha threw mostly fastballs, mixing in a few changeups as well. He is still scheduled to have a follow-up MRI on Monday so that doctors can ensure that Wacha's shoulder is continuing to heal. As long as everything checks out positively, he's expected to continue throwing off the mound every two-to-three days for some time.

"It's a great thing to see," manager Mike Matheny said. "It's a step forward. We're not putting too much pressure on him. I know it's just another step in the process. He has to trust it and keep moving forward."

Whether he heads out on a rehab assignment will be determined by whether he progresses quickly enough to join one of the affiliates before the Minor League regular season ends on Sept. 1. Wacha could also build up his arm strength by throwing simulated games in St. Louis.

"There's definitely been anxiousness," Wacha said. "You want to get out here and want to start throwing, but I understand that you have to take your time with these kinds of injuries. It's important not to rush back too quickly. That's how I've been dealing with it mentally and understanding long-term goals as well."